Electrical apparatus



Dec. 2, 1930. F. FIRESTONE 3,733,234

ELECTRICAL APPARATUS Filed June 6, 1927 22/; IIIIP 3- Patented Dec. 1930UNITED STATES PATENT OFFICE FLOYD IIBESTONE, ANN ARBOR, MICHIGAN,ASSIGNOR TO THE REGENTS OF UNIVERSITY. OF MICHIGAN, OF MICHIGAN ANNARBOR, MICHIGAN, A COBEORATION OF ELECTRICAL APPARATUS Application filed.Tune 6, 1927. Serial No. 196,828.

This application is a continuation in part of my application Serial No.44,955 filed July 20,1925.

My invention relates to a hook-up of electrical apparatus and has forits principal 0bj ect to devise a hook-up by means of which anelectro-magnet or similar device will be made responsive to a singlepulse of electricity or to a current change of momentar Another objectis to devise a means of which an electrical current whose normalintensity is insufficient to operate an electric device in its circuit,will be increased in intensity sufiiciently to operate said device asthe effect of a momentary change in the potential of a controllingelement.

In the accompanying drawing which forms part of this specification,

Fig. l is a diagrammatic view of thehookup of an electrical apparatusconforming to my invention,

Fig. 2 is a diagrammatic view of the plate circuit of the gas contentelectron tube,

Fig. 3 is a diagrammatic view of the grid circuit of said tube; and

- Fig. 4 is a diagrammatic View of the filament circuit of said tube.

Fig. 5 illustrates a modification whereby the plate circuit isautomatically broken.

In the system illustrated in the accompanying drawing there is aphotoelectric, selenium or other light sensitive cell 1 in an electricalcircuit 2 that contains an electric battery 3 and a resistance 4. Theinput of a vacuum tube amplifier A of well known type is shunted acrossresistance 5. The plate 6 of the amplifier tube is electricallyconnected by wires 7 with the grid 8 of a gas content electron tube B'through a condenser 9; and the opposite side of the amplifier platebattery 10 is connected to a potentiometer 11, the output terminals ofsaid amplifier being shunted across a resistance 12 interposed betweensaid condenser 9 and said potentiometer 11. Said potentiometer isconnected to the negative pole of a battery 13 whose positive pole iselectrically connected to the filament 14 of said gas content electrontube B. The grid circuit of said gas content electron tube therefore,(see Fig. 3) contains the resistance 12,

duration. ook-up by the potentiometer 11 and the battery 13. The

filament circuit of said gas content electron tube (see Fig. 4)comprisesthe filament 14 and an ordinary A battery 15. The plate circuitof said gas content electron tube (see Fig. 2) comprises the plate 16thereof, a battery 17 to whose positive side said plate is electricallyconnected through an electromagnet or other suitable electrical device18 and a I switch 19 which is normally closed, and the filament 14 ofsaid gas content electron tube which is connected to the negative sideof said battery.

The function of the filament battery 15 is the usual function of heatingthe filament and causing an emission of electrons therefrom. The mainfunction of the battery 13 is to create a negative potential or bias onthe grid of the electron tube. The principal function of the platebattery 17 is to maintain a positive potential with respect to thefilament 14 on the plate 16. If an electron passes from the filament 14toward the plate 16 at a sufficiently high velocity it may strike amolecule of the gas contained in the tube and cause said molecule to beionized, that is, broken up into a negative charge which proceeds to theplate 16, and a positive charge which returns toward the filament 14. Ifthe grid 8 is held at a sufiiciently large negative potential, very fewelectrons will pass from the filament 14 to the plate 16 with sufiicientvelocity to ionize the gas in their path. Therefore, the plate current(which is composed mainly of these electrons) will be very small. Underthese conditions, most of the electrons which leave the filament 14 willreturn to it. If, however, the negative potential onthe grid 8 should bedecreased, that is, made more positive, an increasing number ofelectrons will travel from the filament 14 to the plate 16, and anincreasing number of gas molecules will be ionized. When a certaincritical value of the potential of the grid 8 is reached, a suificientnumber of positive ions will be formed so that as they return to thefilament and reach the space between the filament 14 and the grid 8, thefield of their positive charges will counteract, near the filament 14,the field of the negative charge on the grid 8, and consequently a largenumand grid has practically her of electrons will be permitted to leavethe filament and travel across to the plate 16. This, in turn, producesa larger number of positive ions which return to the filament so thatfinally practically all of the electrons emitted by the filament 14travel to the plate 16. If the grid is now made more positive than thiscritical value at which the ionization became unstable very littlechange in the plate current will take place. If the id is now made morenegative than the critical value, the ionization will still persistsince the large number of positive ions between the filament eliminatedthe effect of the grid. The original un-ionized condition may berestored by opening the plate circuit.

In operation, the grid potential is normally held at a value at whichthe ionization does not take place. Any source of electromotive force,as, for instance, a vacuum tube amplifier, may be arranged to vary thisgrid potential. If at any time the grid potential should cross thecritical value, then ionization will immediately start and the increasein place current will be suflicient to operate the electromagnet 18 or asimilar device. Now, even though the grid potential may return to itsoriginal value, the current through the magnet 18 will still persistuntil the switch 19 is opened.

- An additional refinement of my invention is shown in Figure 5. If theionization in the tube is permitted to persist for a period of severalhours, the bombardment of the filament by the positive ions of the gaswhich return to it .will finally destroy it. To revent this, a'series ofrelays is arrange to hold the circuit in the operated condition afteronce the ionization has started and immediately cut off the platecurrent in the tube so .that the ionization lasts but a fraction of asecond. While this may be accomplished in a variety of ways, the circuitof Figure 5 is typical. The device to be operated 54 corresponding tothe electromagnet 18 of Figure 1 receives its current, not from the gascontent tube, but from the battery 50 which is controlled by relays 51and 52. The relays are shown in the condition in which they would bewhen the circuit is ready to be operated and there is no ionization inthe tube. If, now, due to a certain input electromotive force, the gascontent tube becomes ionized, the increased plate current will operatethe relay 52, thus breaking the circuit through the battery 50 and thedevice to be operated 54. This same action cuts ofi the current fromrelay 51, thus permitting its armature to connect. the battery 50 torelay 53. Relay 53 breaks the plate circuit of the tube B and stops theionization; relay 52, at the same time, is de-energized, permitting itscontacts to close. However, the current'from the battery 50 cannot nowpass through the device 54 because the circuit is broken in relay 51,the battery 50 still being connected to relay 53. Thus, the deviceremains in the operated condition. When it is desired to re-set thecircuit to its original condition, switch 55 may be momentarily closedand then opened. The closing of the switch 55 energizes the magnets ofrelay 51, thus returning the device 54 to its original condition andalso permitting the magnets of relay 51 to receive their current frombattery 50 through the relay contacts after the switch 55 is opened.

It is noted that in the hook-up illustrated in Figure 5, the out-put ofthe amplifier is connectedto the negative side of the plate battery ofthe gas electron tubeinstead of being connected to the potentiometer, asin Figure 1. In other respects, thechook-up of the two figures issubstantially the same.

In my co-pending application, I have disclosed my invention as appliedto the detecting of flaws in rollers for roller bearings and theautomatic assorting of good and defective rollers. Obviously, however,the electric hook-up hereinbefore described is capable of numerousapplications where it is desired to make a persistent response to asingle pulse of electricity or to a merely momentary condition of anelectrical circuit. Likewise, I do not wish to be limited to the detailsdescribed, for instance the amplifier might be replaced with any othersuitable unit having out-put terminals suitable for cooperating with theinput terminals of the trip relay circuit.

What I claim is:

1. The combination of a gas content electron tube having a filament, acontrol grid and a plate, a substantially steady source of electricalenergy of such strength and so connected to said plate as to normallymaintain a substantially steady plate potential large enough to produceionization of the gas in the tube above a certain grid potential, asource of grid potential large enough to normally overcome the tendencyof the gas in the tube to ionize, means for applying electromotive forceto the grid, and a device in the plate circuit irresponsive to thenormal current therein but responsive to the current therein durin suchionization.

2. The com ination with an electrical amplifier of a gas contentelectron tube having a filament, a control grid and a plate, circuitstherefor, a substantially steady source of electrical energy of suchstrength and so connected to said plate as to normally-maintain asubstantially steady plate potential large enough to produce ionizationof the gas in the tube above a certain grid potential, a source of 'gridpotential large enough to normally overcome the tendency of the gas inthe tube to ionize, means for applying to said grid the output ofelectromotive force from the amplifier to permit ionization of the gasand a device in the plate circuit irresponsive to the normal currenttherein but responsive to the current therein during ionization.

' 3. The combination with an electrical amplifier of a gas contentelectron tube having a filament, a control grid and aplate, circuitstherefor, a substantially steady source of electrical energy of suchstrength and so connected to said tain a substantial y steady platepotential large enough to produce ionization of the gas in the tubeabove a certain grid potentia a source of electrical energy in the gridcircuit large enough to normally overcome the tendency of the gas in thetube to ionize, means for applying to the grid the output ofelectromotive force of the amplifier and" a device in the plate circuitirresponsive to the normal current therein but responsive to the currenttherein during ionization.

4. The combination of a gas content electron tube having a filament, acontrol grid and a plate, circuits therefor, a substantially steadysource of electrical energy of such strength and so connected to saidplate as to normally maintain a substantially steady plate potentiallarge enough to produce ionization over a certain range of gridpotentials, a source of grid biasing potential of suitable value tonormally prevent ionization of the gas in the tube, means for applyingan operating electromotive force ,to the grid, and a device in the platecircuit responsive to the change in the plate current due to suchionization.

5. The combination with an electrical am-. plifier of a gas contentelectron tube having a filament, a control grid and a plate, circuitstherefor, a substantially steady source of electrical energy of suchstrength and so con nected to said plate as to normally maintain asubstantially steady plate potential large enough to produce ionizationof the gas in the tube over a certain range of grid potentials, a sourceof grid biasing'potential of suitable value to normally preventionization of the gas in the tube, means for applying to said grid theoutput of electromotive force from the amplifier to cause ionization ofthe gas, and a device in the plate circuit responsive to the change ofplate current due to such ionization.

6. The combination of a gas content electron tube having a filament, acontrol grid and a plate, circuits therefor, a source of plate potentiallarge enough to produce ionization over a certain range of gridpotentials, a source of grid biasing potential of suitable value tonormally prevent ionization of the gas in the tube, means for applyingan operating electromotive force to the grid, a device in the platecircuit responsive to the change in plate current due to suchionization, and means responsive to'said device for breaking the platecircuit.

7. The combination of a gas content eleclate as to normally main- '.thetube to ionize,

tron tube having a filament, a control grid and a plate, circuitstherefor, a source of plate potential large enough to produce,ionization over a certain range'of grid potentials, a source of gridbiasing potential of suitable value to normally prevent ionization ofthe gas in the tube, means for applying an o crating electromotive forceto the grid, an an electromagnet in said plate circuit'responsive to thechange in the plate current due to such ionization, and a normallyclosed circuit containing a source of electrical energy and anelectromagnet, each of said electromagnets having its armature in andnormally closing the circuit of the other.

8. The combination of a gas content electron tube having a filament, acontrol grid and a plate, a source of plate potential large enough toproduce ionization of the gas in the tube above a certain gridpotential, a

source of grid potential large enough to normally overcome the tendencyof the gas in the tube to ionize, means for applying electromotive forceto the grid, and a device in the plate circuit irresponsive to thenormal current therein but responsive to the current therein during suchionization and a device in the plate circuit for opening and closing thesame.

9. The combination with an electrical amplifier of a gas contentelectron tube having a filament, a control grid and a plate, circuitstherefor, a source of plate potential large enough to produce ionizationof the gas in the tube source of grid potential large enough to normallyovercome the tendency of the gasin means for applyingto said grid theoutput of electromotive force from the amplifier to permit ionization ofthe gas and a device in the plate circuit irresponsive to the normalcurrent therein but responsive to the current therein during ionization,and means. for restoring said tube to un-ionized condition.

10. The combination of a gas content electron tube having a filament,,acontrol grid and a plate, circuits therefor, a source of plate potentiallarge enough to produce ionization over a certain range of gridpotentials, a source of grid biasing potential of suitable value tonormally prevent ionization of the gas in the tube, means for applyingan operating electromotive force to the grid, and a device in the platecircuit responsive to the change in the plate current due to suchionization and a device in the plate circuit for opening the circuitthereof.

Signed at Detroit, Michigan, this 4th day of June, 1927'.

FLOYD FIRESTONE.

above a certain grid potential, a

